Pulmonary enteric adenocarcinoma

Pulmonary enteric adenocarcinoma (PEAC) is an exceptionally rare subtype of non–small cell lung cancer (NSCLC). It is characterized by pathological features similar to those of colorectal adenocarcinoma. Most patients with PEAC have almost no special clinical manifestations, and it is often difficult to differentiate from metastatic colorectal adenocarcinoma (MCRC). As a special type of lung adenocarcinoma, PEAC has unique mutation expression and immune characteristics; its mutation profile shows higher Kirsten rat sarcoma viral oncogene (KRAS), human epidermal growth factor receptor-2 (HER2) , DNA mismatch repair(MMR) mutation rates, and much lower epidermal growth factor receptor (EGFR) rate. So in the future, targeted therapy may tend to be a new light in the treatment of PEAC. As for immunohistochemistry (IHC), CDX-2, villin, and CK7 are significantly positive in PEAC. This review focuses on the pathologic features, immunohistochemical examination, mutation analysis, diagnosis, treatment, and prognosis of PEAC.